1. Field of the Invention
The present invention relates to a joint device for a lubricating system that is inserted into a container with a lubricant, such as oil, and that is also comprised of a casing that encloses an outlet conduit for the removal of the lubricant from the container. Moreover, the invention relates to a pump apparatus for producing a subpressure in a milking machine. The pump apparatus includes a pump having a suction side, a pressure side, and a lubrication device for lubricating the pump apparatus.
2. Description of the Prior Art
Today, milking machines operated by vacuum pumps are used in barns. In order to guarantee a high level of uniform milk production and ensure the health of the animals, the pumps must work in a highly reliable manner. Lubrication of the pump and especially its bearings is very important in achieving such reliability.
A usual type of pump device used today is shown in FIG. 1 labeled "Prior Art." The pump device includes a vacuum pump 1 having a suction side 2, a pressure side 3, and terminating in an outlet tube 4. A lubricator 5 comprised of an oil container 6 and an oil distributor (not shown) delivers oil to the bearings of vacuum pump 1. With the aid of the oil distributor (not shown), it is possible to guide the oil flow to the bearings of vacuum pump 1 via oil conduits 7. A silencer 8 and an oil trap 9 are provided on the pressure side 3 of vacuum pump 1. Both silencer 8 and oil trap 9 separate the oil which is then carried by air on pressure side 3 to oil containers 6a and 6b. Several problems are associated with this known pump device. First, container 6 on lubricator 5 must be filled with new oil before it empties in order to prevent jamming of the bearings. Therefore, continuous supervision of the oil level in container 6 is necessary. Oil containers 6a and 6b are connected to oil trap 9 and silencer 8. Oil containers 6a and 6b collect the separated oil and must be continuously supervised in order to prevent oil flowing onto the floor. The oil flow through lubricator 5 is controlled by a valve that directly influences the oil flow by throttling or opening a passage through which the oil flows. The amount of oil delivered in this manner through the valve is very difficult to regulate in an accurate manner. Furthermore, the outlets are sensitive to particles of dirt or thickened accumulations of oil that can stop up the outlets. Because the oil flow from lubricator 5 may not be observed, it is difficult to determine how much oil has been delivered to vacuum pump 1. Oil consumption increases if, for example, any one of the shaft bearings of the vacuum pump is leaking oil. Since this increase of oil consumption may not be observed, such a leakage may lead to the breakdown of the bearings. Furthermore, the function of lubricator 5 is very sensitive to a small inclination which results in an unequal distribution of oil to oil conduits 7 and to the different pump bearings. Moreover, lubricator 5 demonstrates an open construction that gives rise to a risk of accumulation of dirt in the oil. Consequently, the bearings may be supplied with impurities. In addition, the handling of the known lubricating system is relatively complicated. The new container 6 with new oil must be replaced in lubricator 5 when the oil in old container 6 runs out. Moreover, containers 6a and 6b must be replaced regularly because separated oil is collected therein.
German Patent No. 3711000 discloses an oil container for combustion engines with dry sump lubrication. In order to reduce noise, this oil container includes a return conduit having an orifice in a conical pipe. Thus, the mixture of oil and air that is brought back to the oil container may expand in the pipe with the oil depositing on the wall of the pipe by means of a helicoidal movement. The oil to be transported from the container is sucked out through a separate pipe in the lower portion of the container.
French Patent No. 2599843 discloses a device for the refining of oil. The device is comprised of a container having an inlet conduit leading to a first chamber with a sloping bottom wall. Impurities are collected in a lower space and oil is sucked out via an outlet conduit from a second chamber by means of a pump.
German Patent No. 2732474 discloses an oil suction socket for a lubricating system that is intended to be inserted into a container with oil. The suction socket includes an opening provided in the lower portion of the casing that is otherwise closed.
Swedish Patent No. 454 198 discloses a lubricant container attached to an engine. Within the lubricant container, there is a second smaller container which encloses an outlet conduit for the removal of lubricant from the lubricant container and an inlet conduit for the supply of lubricant to the lubricant container. The second smaller container is not inserted into the lubricant container, but is an integral, fixed part of the lubricant container. SE-B-454 198 does not suggest any means for separating air from the lubricant supplied to the lubricant container.
Swedish Patent No. 2 529 842 discloses a lubricating system having a pump device immersed in a lubricant container. The pump device includes an outlet means for the removal of lubricant to a machine to be lubricated. Lubricant is supplied to the lubricant container by means of further conduits separated from the pump device.